Simple Application Configuration Library

Introduction

A Java framework to read and update configuration entries which is being used in your application with support for many different 'sources' where the configuration values can come from with ability to update the internal setup of the framework during runtime.

Generic implementations of 'common' types of sources are also provided for ease of use.

The framework has been specifically coded to support Java version from 5 upwards for use in enterprise systems where the version of Java may be restricted to older versions.

Maven Module Structure.

The Framework is broken down into three main maven dependencies.

• scs-parent - The parent pom.
• scs-api - The base framework and minimal implementations.
• scs-impl - Meta dependency to include all sub implementation modules, such as caching, database, text expansion, etc

SCS-PARENT

Maven POM to build the project from source.

SCS-API

Maven JAR Artifact which provides the base framework for configuration instances including a Thread safe memory base implementation.

Usage

The main class into the API is the com.github.scs.Configuration which provides a builder pattern for creating configuration instances and defining sources.

import com.github.scs.Configuration;
import com.github.scs.impl.MemoryConfigurationSource;

public class ConfigurationBuilderUsage {
    public static void main(String[] args) {
        MemoryConfigurationSource memorySource = new MemoryConfigurationSource();
        
        Configuration.ConfigurationBuilder configurationBuilder = Configuration.builder();
        Configuration configuration = configurationBuilder.source(memorySource).build();

        configuration.store("some-string-key", "value-of-some-key");
        System.out.println(configuration.retrieve("some-string-key"));

        configuration.storeBoolean("some-boolean-key", Boolean.TRUE);
        System.out.println(configuration.retrieveBoolean("some-boolean-key"));

        configuration.storeInteger("some-int-key", 22);
        System.out.println(configuration.retrieveInteger("some-int-key"));
    }
}

Additionally, a Global Configuration instance is provided to the system via the com.github.scs.GlobalConfiguration object which can be configured as per the below example.

public class ConfigurationBuilderUsage {
    public static void main(String[] args) {
        ConfigurationSource propertiesSource = new PropertyFileConfigurationSource("application.properties");
        ConfigurationSource dataBaseSource = new DataBaseSource("DB_TABLE_NAME");
        
        ConfigurationDefaults defaults = ConfigurationDefaults.buildCommon();
        GlobalConfiguration.configure(defaults, propertiesSource, dataBaseSource );
        
        String myConfigEntry = GlobalConfiguration.instance().retrieve("SomeKey", "DefaulValueIfNotFound");
    }
}

Maven Dependency

<dependency>
    <groupId>com.github.scs</groupId>
    <artifactId>scs-api</artifactId>
    <version>${scs.version}</version>
</dependency>

SCS-IMPL

Maven Dependency

<dependency>
    <groupId>com.github.scs</groupId>
    <artifactId>scs-impl</artifactId>
    <version>${scs.version}</version>
</dependency>

SCS-IMPL-CACHING

Maven module which provides caching implementations of the com.github.scs.api.ConfigurationSource interface.

The following implementations are provided at the moment

• com.github.scs.impl.GuavaCacheConfigurationSource Implementation of a ConfigurationSource which supports caching of the values retrieved by an underlying source by using the LoadingCache provided by Google's Guava library

• com.github.scs.impl.EHCachedConfigurationSource Implementation of a ConfigurationSource which first will delegate the retrieve operation to the configured underlying source and then cache the result of this delegation based on the caching configuration. This implementation supports both programmatic as well as external EHCache configurations

• com.github.scs.impl.EHMemoryCachedConfigurationSource - Simpler API version of the EHCachedConfigurationSource which configures the cache to use memory only with some sane defaults for max entries, time-to-live and time-to-idle. For more complex caching requirements it is adivsed to use the more generic EHCachedConfigurationSource

Maven Dependency

<dependency>
    <groupId>com.github.scs</groupId>
    <artifactId>scs-impl-caching</artifactId>
    <version>${scs.version}</version>
</dependency>